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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        // 练习： 调用数据，查找链
        function  F1(age) {
            this.age = age;
        }
        function F2(age) {
            this.age = age;
        }
        // F2原型指向F1实例
        F2.prototype = new F1(11);
        function F3(age) {
            this.age = age;
        }
        // F3原型指向F2实例
        F3.prototype = new F2(12);
        // 实例化F3
        var f3 = new F3(13);
        console.log(f3.age);
        // 值是13，因为自身拥有age，不会去原型找
    </script>
</body>
</html>